Jet thrust controller for ground effect machine



W. F. CARR July 26, 1966 JET THRUST CONTROLLER FOR GROUND EFFECT MACHINE Filed Sept. 6, 1962 2 Sheets-Sheet 1 July 26, 1966 w. F. CARR 3,262,511

JET THRUST CONTROLLER FOR GROUND EFFECT MACHINE Filed Sept. 6, 1962 2 Sheets-Sheet 2 INVENTOR. 33g. 4

Mal/4M 6422 B United States Patent 3,262,511 JET THRUST CONTROLLER FOR GROUND EFFECT MACHINE William F. Carr, Santa Monica, Calif, assignor to Douglas Aircraft Company, Inc, Santa Monica, Calif.

I Filed Sept. 6, 1962, Ser. No. 221,687 5 Claims. (Cl. 180-7) This invention relates to means for controlling and utilizing the jet thrust produced by a ground effect machine which is supported above the ground level by a cushion of air forced beneath the body and retained by an air curtain produced by the issuance of air under pressure through a substantially continuous peripheral downwardly exiting jet slot around the periphery of the machine.

In the type of machine under consideration, the jet slot is directed substantially vertically downwardly and any jet reaction is vertical and has no horizontal component. In those cases where the jet slots are angled downwardly and inwardly toward the longitudinal axis of the machine the jets still do not have any fore and aft horizontal component and their lateral horizontal components balance each other out. In order to gain at least a measure of propulsion and steering, some previous ground effect machines have been provided with a plurality of guide plates or vanes extending generally vertically in the jet slots and arranged in spaced relation in the manner of the slats of a Venetian blind. The slats were rigid plates, each separately mounted on a cross axle and control means were provided to tilt them to various angles to obtain forward or rearward thrust components. By tilting the vanes or slats at opposite sides in opposite directions the machines could be steered in the manner of caterpillar tractors.

The machines mentioned above have functioned generally in a satisfactory manner but they have some disadvantages and do not comply with all of the criteria which have been set up for vehicles of this class. Among other things, the vanes should be inexpensive and easily maintained or replaced. They should not be adversely affected by ice, salt water, sand, dust, dirt or small objects such as stones carried by the high velocity air jet. The vanes should present a smoothly curved flow pattern contour to the jet stream in all positions of adjustment.

In addition to fore and aft deflection it should be possible to so adjust the vanes as to produce lateral components for hover control to assist, for instance in urging the vehicle laterally to a position at a loading dock. The control vane movement should not be impeded or altered by damage to the side walls of the jet slot such as caused by dents, gunfire (in the case of military vehicles), or other minor mechanical damage, or even by damage such as gunfire punctures in the vanes themselves.

The known prior art constructions are mechanically quite complicated, with many links, levers, and couplings, which are quite subject to damage and malfunction and are difiicult to repair and replace. Corrosion and erosion result in a relatively short service life. Even relatively minor damage to the vanes or the walls of the jet slots will usually cause mechanical interference and prevent operation. The rigid vanes cannot be made to present a curved guiding surface to the issuing air in their various positions of adjustment. A lateral thrust component cannot be introduced without greatly complicating the control and linkage mechanism.

The present invention overcomes all of the problems pointed out above and meets all of the presently estab lished criteria for performance, safety, and maintenance. A plurality of flexible, preferably elastomeric, vanes are mounted in each jet slot and spaced longitudinally much as the prior art vanes. Each vane, in its position of rest,

is substantially planar and extends across substantially the full width of the jet slot. The upper end of each vane is made rigid by the use of The stiffness of the vane is gradually reduced toward its lower end so that when such end is displaced forwardly or rearwardly the vane will have a smoothly curved contour with the radius of curvature gradually decreasmg toward the lower end to control the air flow smoothly and to produce the optimum change of direction. The presently preferred way to produce this characteristic is to mold a reinforcing plate of steel or other elastic material into the body of the vane, the plate being rigidly secured to the hanger inassembly. To vary the resistance to bending, the plate has a decreasing cross-sectional area as it approaches the lower end. This is accomplished most readily by tapering the width of a plate of uniform thickness.

In the presently preferred form, a control rod extends across and is secured to the lower ends of the elastomeric body and the reinforcing plate. An axially extending, axially movable control member is mounted in a compartment at each side of the jet slot, and the ends of each control rod pass through clearance openings in the jet slot wall and are connected to the control 'members preferably by a ball joint or its equivalent. The control members for each jet slot are connected by suitable linkage to a pilot operated control mechanism which is adapted to move the pairs of control members simultaneously in the same or opposite directions at opposite sides of the longitudinal axis of the vehicle to accomplish forward or reverse propulsion or steering.

In addition, the control mechanism can, separately or simultaneously with the other movements, cause the control members of one pair to move in opposite directions. This action produces a twist in each vane about its longitudinal axis. If the vane has been adjusted either forwardly or rearwardly so that there is a horizontal component being produced, this component will now be angled laterally and the vehicle can be sidled up to a dock or other desired location Without changing its heading.

The vane bodies are preferably rubber or neoprene which are substantially free from corrosion or erosion. The reinforcing plate does not extend to the vertical marginal edges which therefore remain quite flexible and can be urged past dents or other obstructions along the jet slot wall with very little added force. Because of the general flexibility of each vane assembly even gunfire damage will not ordinarily prevent continued operation. Each vane is mounted to the slot walls with a few bolts and may be removed and replaced in a few minutes in case of excessive damage.

Many other advantages and features of novelty will become apparent as the description proceeds in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of a ground effect machine embodying the invention;

FIGURE 2 is a sectional view in elevation showing in idealized form the air supply, ducts, and discharge passage extending longitudinally of one side of the machine;

FIGURE 3 is a vertical sectional view taken on line 33 of FIGURE 2;

FIGURE 4 is an elevational view partly in section, taken on line 4-4 of FIGURE 3;

FIGURE 5 is an elevational view, partly in section showing the details of construction of a vane assembly; and

FIGURE 6 is a perspective view showing in idealized form a pilot controlled mechanism for actuating the guide vanes.

The ground effect machine depicted in FIGURE 1 comprises a body which is generally rectangular in planform and is provided with a centrally located cargo deck 12. Clustered together across the forward portion of the vehicle are the pilots compartment 14 and left and right air intake hoods 16 and 18. Adjacent the rear portion of the vehicle are a second pair of laterally spaced air intake hoods 20 and 22. Pins 24 support a horizontal stabilizer 26 and conventional rudders and elevator are carried by these elements for controlling the course of the vehicle in forward flight. Thrust propellers 28 are mounted for rotation at the rear of the fins 24.

As will be seen from FIGURE 2, each of the hoods 16 and 20 serves as the air intake for a fan 30, 32 respectively and merges with a pressure air duct 34, 36 serving the quadrant of the vehicle in which its fan is located. Similar fans and ducts are associated with hoods 18 and 22 at the right hand side of the vehicle. The ducts supply air under pressure to the jet slot or air discharge passage 38 and to a similar passage at the right hand side of the machine. In the presently preferred embodiment of the invention a single gas turbine 40 provides the power for the four air supply fans and the two propellers. Shafts 42 and 44 transmit power from the turbine to the two fans and 32, shown in FIGURE 2, and similar shafts transmit power to the other two fans.

The jet slot or air discharge passage 38 is shown in FIGURE 3 as being formed by two vertical walls 46 and 48. Compartments 50 and 52 are formed adjacent thereto by outer walls 54 and 56. In a variant of the construction all of the walls may be angled inwardly and downwardly. Also while the walls are shown parallel their relation may be varied in accordance with design objectives. Thus, in the illustrated embodiment the cross-section of the passage is rectangular.

The passage 38 is divided longitudinally into a plurality of separate air fiow paths by the plurality of guide vanes 58. These vanes are rectangular in shape in the present instance and fit in passage 38 with working clearance. Each vane is rigidly attached to the walls of the passage at its upper end, and its lower end is free to move longitudinally forward and rearward as indicated in dotted lines in FIGURE 4. As will be explained in more detail it is also free to twist about its longitudinal (vertical) axis. The details of construction of the vane are best shown in FIGURE 5. The main body 60 of the vane is preferably made of rubber, neoprene, or other suitable elastomeric material. In its position of rest, when it is hanging vertically, it is generally planar. A thin planar reinforcing plate 62' of steel or other elastic material is embedded in the vane body and extends throughout the length of it, projecting a short distance at its upper end. A rigid block or hanger 64 encompasses the upper ends of both the vane body and the plate, being bonded to the former and secured to the latter by suitable fasteners such as bolts and nuts, or rivets, as indicated at 66.

The elastic nature of plate 62 causes the vane to assume a smoothly curved contour to guide the air flow when the lower end of the vane is deflected. In order to produce a graduated curvature with a decreasing radius toward the lower end, the plate is formed with a decreasing crosssectional area which, in the present case, is accomplished by tapering the plate in planform. If desired, the taper can be uniform from end to end rather than as shown. While a single plate is illustrated, it is obvious that a plurality of narrow strips could be substituted to serve the same purpose.

The hanger 64 is rigidly attached to the upper portions of walls 46 and 48 by bolts 68 or other suitable fastening means. Consequently the upper end of the vane assembly remains vertical at all times and the curvature gradually increases from top to bottom, as shown in FIGURE 4, when the lower end is deflected. Thus the direction of air flow is gradually changed with a minimum loss of energy and is so directed as to produce a substantial horizontal thrust component. Additional reinforcement for the margins of the elastomeric vane body may be provided by the cables 70 which are molded in place similarly to plate 62. The cables are quite flexible and modify the elastic action of the assembly only slightly.

In order to provide means for controlling the movement of the lower end 'of the vane a control rod 72 is provided. This rod is secured to the vane body and reinforcing plate by fasteners 74 and its free ends extend beyond the margins of the assembly, passing through clearance openings 76 in the walls 46 and 48. An elongate longitudinally movable control member 78, 80, actuated by means about to be described, is mounted for movement in each of compartments 50, 52. Each of these control members is provided with a series of ball formations 82 which may be conveniently swaged in place. Members 78, 80 are substantially rigid rods to act as push-pull members but they may be hollow tubing or cables with stiffening tubing swaged thereon. In the case of substantial longitudinal curvature in the discharge passages a flexible cable may be substituted, necessitating turn-around pulleys and return passes of cable to an actuating bell crank.

The ends of the control rods are formed as split ballsockets 84, 86 to surround the ball formations 82, the sockets being secured together by conventional fasteners, not shown. Considering FIGURE 5, if both members 78 and are moved out of the plane of the paper the lower end of the vane will move rearwardly and direct the air to produce a forward thrust. If members 78 and 80 are moved into the plane of the paper the reverse effect is produced. If the members are moved relatively in opposite directions rod 72 will be turned and produce a spiral twist in the vane. If the vane is out of its neutral 'position at the time, the horizontal thrust compound will be rotated laterally.

For exemplary purposes only, a form of pilot operated mechanism is shown in FIGURE 6 to actuate the control members at each side of the vehicle in the various modes necessary to accomplish the desired control. A floor portion 90 in the pilots compartment bears a central support post 92 having a ball socket 94 at its upper end. The floor portion also carries two bearing brackets 96, 98 having horizontal, axially aligned bearings 100, 102 for the reception of rotatable shafts 104, 106. The virtual pivot point of ball socket 94 is in alignment with bearings 100, 102. Control column 108, having handle 110, is mounted by its lower ball end 112 in the socket 94 for universal movement.

Shafts 104 and 106 carry at their outer ends rigidly mounted bell cranks 114, 116 which in turn are connected by push-pull rods 118 and 120 with the mid-portion of whillletrees 122 and 124. It will be apparent that rotation of shafts 104 and 106 will move control elements 78, 80 on each side back or forth depending on the direction of rotation. Bell cranks 126 and 128 are rotatably mounted on shaft 104 and 106 and are connected at their lower ends to push-pull rods 130 and 132. These rods in turn are connected to the inner ends of whiffietrees 122 and 124. When bell cranks 114 and 126 move in unison there is no relative movement of members 78 and 80 but if they rotate with respect to each other the whiffietree will pivot about its midpoint and produce relative movement of members 78 and 80.

Stud posts 134 and 136 extend upward from bell cranks 126 and 128 and at their upper ends are pivotally connected with bell cranks 138 and 140 pivotally mounted on posts 142 and 144 fixedly attached to shafts 104 and 106. Arms 146 and 148 of these bell cranks are connected by universal pivots to links 150 and 152 which in turn are connected by universal pivots to the outer end of arm 154 which is rigidly attached to the control column 108.

The inner ends of shafts 104 and 106 are bifurcated t0 form clevises 156 and 158 which pivotally receive the lower ends of links 160 and 162. A tie bar 164 extends laterally and is pivotally attached at 166 to control column 108. Its ends 168 and 17%} are formed as ball-socke to universally pivotally engage the upper ends of links 169 and 162.

It will be seen now that if the control column 1% is tilted forward as seen in FIGURE 6 all of the mechanism shown therein will move in unison, rotating about the axis of bearings 1% and 102. Crank arms 114-, 11116, 126, and 128 will all turn through the same angle. Rods U8 and 120 will move the whiffletrees rearwardly and rods 13% and 132, moving the same amount, will keep the whiflletrees parallel to their original attitudes. Thus, the lower ends of all of the vanes are moved rearwardly to form smoothly curved paths for the rearward discharge of air to produce a forward thrust component. Tilting column 108 rearwardly will act in the same Way to produce a rearward thrust component.

If the column 103 is tilted forward, for example, to some extent so that there is a forward horizontal thrust component and it is now also tilted to the left, it will be seen that tie bar 164 will move to the left, tilting links 160 and n22 in their common plane. This action produces no effect on shafts 1M and 1% so no relative motion results. However the lateral tilting of the column also moves arm 154 laterally and it, in turn, moves links 156 and 152 to the left. Link 150 moves bell crank 138, 146 counter-clockwise, tilting stud post 134 rearwardly and bell crank 126 forwardly. This motion in turn moves rod 130 forwardly with respect to rod 118, turning 'whiflletree 12.2 counter-clockwise. Control element 78 moves rearwardly and control element 39 moves forwardly, rotating all of the control rods 72 counter-clockwise. As a result the forward thrust component is rotated so that a combination. of forward and lateral thrust is obtained, urging the vehicle to the left.

The reverse action takes place on the right hand side of the vehicle, with rod 132 moving rearwardly to rotate the whiffletree and the control rods counter-clockwise and produce an identical leftward component. Since the two lateral forces are acting in the same direction the vehicle can be sidled up to a dock or the like without changing its heading. The lateral forces can be produced with no turning moment and no longitudinal movement by dividing the vanes to fore and aft groups with a mechanism like that of FIGURE 6 for each group. The two groups can then be manipulated to produce lateral forces in the same direction and balancing longitudinal forces in opposite directions. Provision is then made for locking the groups together for the other operations.

When the column 1% is rotated about its vertical axis, tie bar 164 rotates with it and turns links 160 and 162 in opposite directions. Consequently shafts 1M and file are rotated in opposite directions producing forward thrust on one side and rearward thrust on the other so that the vehicle can be steered somewhat in the manner of a caterpillar tractor. It will be noted that rotation of column l d-it will rotate arm 154 and move the associated linkage so that the vanes 58 will be twisted to some extent. How ever the twist is in a direction to complement the turning action desired and hence is not objectionable. If, in some instances, it is desired to reduce the amount of twist it can be readily accomplished by tilting the column laterally in the opposite sense to any desired extent.

It will be seen that the invention described above overcomes the di-sadvantages pointed out and provides a novel and useful construction suitable for operation in any environment including warfare. It requires a minimum of maintenance and provides maximum maneuverability and ease of control.

It will be apparent to those skilled in the art that various changes and modifications may be made in the construction and arrangement of parts without departing from the spirit of the invention and it is intended tha-tall such be embraced within the being formed of flexible material and being generally planar and arranged generally vertically in neutral position and extending across the major portion of the width of the passage, the upper end of each vane being mounted in a fixed location and the lower end being movable to produce a curved guiding surface; an elongate control member longitudinally movable in each of said control compartments; clearance openings in the side walls of each passage; a laterally extending cross member attached to the lower end of each vane and having end portions extending through the clearance openings and connected to the control members for movement thereby; and means to actuate the control members to move the lower ends of said vanes to selected forward and rearward positions to define a series of curved exhaust paths introducing a longitudinal thrust component into the air discharge.

2. A ground effect machine comprising: a load supporting body; at least one longitudinally extending, downwardly opening air discharge passage laterally spaced at each side of the longitudinal axis of said body; means to supply air under pressure to said passages to produce downwardly directed air curtains; a plurality of longitudinally spaced guide vanes in each of said passages, each of said vanes being formed of flexible material and being generally planar and arranged generally vertically in neutral position and extending across the major portion of the width of said passage, the upper end of each vane being mounted in a fixed location and the lower end being movable to produce a curved guiding surface; and control means connected to said vanes and actuatable to curve said vanes forwardly or rearwardly to produce a longitudinal thrust component, and to twist said vanes individually about their vertical axes in any position of adjustment to produce a lateral thrust component; said control means including members connected to the lower ends of each vane at laterally spaced points and movable differentially longitudinally to cause laterally spaced points of each vane to move to differential longitudinal positions and introduce corresponding twists in each vane.

3. A machine as claimed in claim 2; and a pilot operated control column mounted for three axes of movement and so connected to said control means that movement of the column about a first axis curves all of the vanes in the same longitudinal direction, movement about a second axis curves the vanes in opposite longitudinal directions on opposite sides of the longitudinal axis of the body, and movement about a third axis twists all of said vanes individually about their vertical axes in the same sense of rotation.

i. A ground effect machine comprising: a load supporting body; at least one longitudinally extending, downwardly opening air discharge passage laterally spaced at each side of the longitudinal axis of said body; means to supply air under pressure to said passages to produce downwardly directed air curtains; a plurality of longitudinally spaced guide vanes in each of said passages, each of said vanes being formed of flexible material and being generally planar and arranged generally vertically in neutral position and extending across the major portion of the width of said passage, the upper end of each vane being mounted in a fixed location and the lower end being movable to produce a curved guiding surface; a pair of laterally spaced, elongate, longitudinally movable control members extending adjacent the lower ends of each row of said vanes and secured to each vane at laterally spaced points; and means to actuate said control members to move the lower ends of said vanes to equally displaced forward and rearward positions to define a series of curved exhaust paths introducing a longitudinal thrust component into the air discharge, and to move the lower ends of said vanes to diiferentially displaced forward and rearward positions to introduce a lateral thrust component into the air discharge.

5. A machine as claimed in claim 4-; the actuating means for the control members being operable to cause all of the control members to move in the same longitudinal direction at one time, and to cause the control members at one side of the longitudinal axis to move longitudinally opposite to those on the other side, and to cause the control members at either side to move in opposite directions at any time regardless of the relative longitudinal positions of the control members.

References Cited by the Examiner UNITED STATES PATENTS 1/1915 Porter. 2/1956 Ross.

10/1961 Cochran 244-52 X 6/1963 Wilder 6035.54 4/1964 Alper et a1. 1807 9/1964 Walker 1807 12/1964 Cockerell 180-7 OTHER REFERENCES Symposium on Ground Effect Phenomena, Princeton University Oct.

21-23, 1959; fig. 5 on page 158 with text 15 page 154; and fig 1 on page 224 with text pages 219-220.

Examiners. 

2. A GROUND EFFECT MACHINE COMPRISING: A LOAD SUPPORTING BODY; AT LEAST ONE LONGITUDINALLY EXTENDING, DOWNWARDLY OPENING AIR DISCHARGE PASSAGE LATERALLY SPACED AT EACH SIDE OF THE LONGITUDINAL AXIS OF SAID BODY; MEANS TO SUPPLY AIR UNDER PRESSURE TO SAID PASSAGES TO PRODUCE DOWNWARDLY DIRECTED AIR CURTAINS; A PLURALITY OF LONGITUDINALLY SPACED GUIDE VANES IN EACH OF SAID PASSAGES, EACH OF SAID VANES BEING FORMED OF FLEXIBLE MATERIAL AND BEING GENERALLY PLANAR AND ARRANGED GENERALLY VERTICALLY IN NEUTRAL POSITION AND EXTENDING ACROSS THE MAJOR PORTION OF THE WIDTH OF SAID PASSAGE, THE UPPER END OF EACH VANE BEING MOUNTED IN A FIXED LOCATION AND THE LOWER END BEING MOVABLE TO PRODUCE A CURVED GUIDING SURFACE; AND CONTROL MEANS CONNECTED TO SAID VANES AND ACTUATABLE TO CURVE SAID VANES FORWARDLY OR REARWARDLY TO PRODUCE A LONGITUDINAL THRUST COMPONENT, AND TO TWIST SAID VANES INDIVIDUALLY ABOUT THEIR VERTICAL AXES IN ANY POSITION OF ADJUSTMENT TO PRODUCE A LATERAL THRUST COMPONENT; SAID CONTROL MEANS INCLUDING MEMBERS CONNECTED TO THE LOWER ENDS OF EACH VANE AT LATERALLY SPACED POINTS AND MOVABLE DIFFERENTIALLY LONGITUDINALLY TO CAUSE LATERALLY SPACED POINTS OF EACH VANE TO MOVE TO DIFFERENTIAL LONGITUDINAL POSITIONS AND INTRODUCE CORRESPONDING TWISTS IN EACH VANE. 